Emergency notification systems typically include a plurality of notification appliances, such as strobes and horns, for providing occupants of a building with a prominent visual or auditory indication of a hazardous condition, such as the presence of smoke or fire. It is not uncommon for notification systems to include dozens, or even hundreds, of notification appliances distributed throughout a building. Servicing such a large number of appliances can be tedious and time-consuming, especially if uninstalling and reinstalling each appliance involves a lengthy or complicated process.
Typically, a notification appliance is attached to an electrical backbox, which is, in turn, mounted on a wall or ceiling surface (e.g., surface mounted or wire mold mounted) or embedded in a wall. Electrical leads or wires extend from a notification system circuit into the backbox through knock-outs in the rear or sides of the backbox. A mounting plate is typically used to attach a notification appliance to the front of the backbox, with audible and/or visual alarm-generating elements of the notification appliance fastened to the mounting plate and having electrical leads extending through the mounting plate and into the backbox. A housing or faceplate is typically placed over the notification appliance and is fastened to the back plate for providing the notification appliance with a secure enclosure.
Many conventional notification appliance enclosures have housings that are secured with one or more screws or other mechanical fasteners that must be fastened and unfastened with a tool during mounting and removal of the housing, respectively. Such fastening and unfastening can take an undesirably long amount of time, especially when aggregated over a large number of appliances. Nonetheless, screws and other such fasteners are commonly employed to provide appliance enclosures with sufficient robustness to satisfy industry standards. For example, Underwriters Laboratories (UL) requires that notification appliance enclosures be able to withstand certain impact forces without opening or being significantly damaged.
In view of the foregoing, it would be desirable to provide a robust notification appliance enclosure that can be opened and closed in a relatively short period of time (e.g. less than five seconds), with relatively little effort and without the use of specialized tools or separate fasteners. The design should provide this easy access while also being robust enough to meet existing UL impact standards.